SAFETY PRECAUTIONS ......................................................................................................2
PRODUCT SAFETY NOTICE................................................................................................3
SERVICING PRECAUTIONS ................................................................................................4
AGENCY REGULATORY INFORMATION ............................................................................8
TABLE OF CONTENTS ........................................................................................................9
SPECIFICATIONS................................................................................................................11
FEATURES AND FUNCTIONS............................................................................................22
PWB ADJUSTMENTS ........................................................................................................49
TROUBLESHOOTING FLOW CHARTS..............................................................................95
DC VOLTAGE ......................................................................................................................96
WAVEFORMS ..................................................................................................................108
REPLACEMENT PARTS LIST ..........................................................................................114
EXPLODED VIEW ............................................................................................................138
PRINTED CIRCUIT BOARDS ..........................................................................................148
CONNECTION DIAGRAM ................................................................................................160
BLOCK DIAGRAM ............................................................................................................161
BASIC CIRCUIT SCHEMATIC DIAGRAM ........................................................................162
FINAL WIRING DIAGRAM ................................................................................................175
MAJOR ICS & UNITS ........................................................................................................179
PA
50V500/LC37
60V500A/LC37F
No. 0178
NTSC
LC37 Chassis
LC37F Chassis
R/C: CLU-5729TSI
CAUTION: Before servicing this chassis, it is important that the service technician read the
"Product Safety Notices" in this service manual.
SAFETY NOTICE
USE ISOLATION TRANSFORMER WHEN SERVICING
Components having special safety characteristics are identified by a
on the parts list in this
Service Data and its supplements and bulletins. Before servicing the chassis, it is important that
the service technician read and follow the "Safety Precautions" and "Product Safety Notices" in
this Service Manual.
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
LCD REAR PROJECTION TELEVISION
JUNE 2003
HHEA-MANUFACTURING DIVISION
!
OPTICAL ENGINE REMOVAL PROCEDURE ..................................................................181
NOTE: This product is to be serviced at board level.
Updated 08/05/05
Updated 07/12/05
TO GO TO A CHAPTER, CLICK ON ITS HEADING BELOW
Updated 04/05/07
Version 0178.09
Updated 01/04/07
2
LC37/LC37F
+ -
LEAKAGE
CURRENT
TESTER
DEVICE
UNDER
TEST
TEST ALL
EXPOSED
METAL
SURFACES
2-WIRE CORD
(READING
SHOULD NOT
BE ABOVE
0.5 mA)
EARTH
GROUND
ALSO TEST WITH
PLUG REVERSED (USING
AC ADAPTER PLUS
AS REQUIRED)
NOTICE: Comply with all cautions and safety-related notes
located on or inside the cabinet and on the chassis or optic unit.
WARNING: Since the chassis of this receiver is connected to
one side of the AC power supply during operation, whenever the
receiver is plugged in service should not be attempted by any-
one unfamiliar with the precautions necessary when working on
this type of receiver.
The following precautions should be observed:
1. Do not install, remove, or handle the optic unit in any manner
unless shatterproof goggles are worn. People not so equipped
should be kept away from the optic unit while handling.
2. When service is required, an isolation transformer should be
inserted between power line and the receiver before any serv-
ice is performed on a "HOT" chassis receiver.
3. When replacing a chassis in the receiver, all the protective
devices must be put back in place, such as barriers, nonmetal-
lic knobs, adjustment and compartment cover-shields, isolation
resistors, capacitors, etc.
4. When service is required, observe the original lead dress.
5. Always use the manufacturer's replacement components.
Critical components as indicated on the circuit diagram should
not be replaced by another manufacturer's. Furthermore, where
a short circuit has occurred, replace those components that
indicate evidence of overheating.
6. Before returning a serviced receiver to the customer, the serv-
ice technician must thoroughly test the unit to be certain that it
is completely safe to operate without danger of electrical shock,
and be sure that no protective device built into the receiver by
the manufacturer has become defective, or inadvertently
defeated during servicing.
Therefore, the following checks should be performed for the con-
tinued protection of the customer and service technician.
Leakage Current Cold Check
With the AC plug removed from the 120V AC 60Hz source, place
a jumper across the two plug prongs. Using an insulation tester
(DC500V), connect one lead to the jumpered AC plug and touch
the other lead to each exposed metal part (antennas, screwheads,
metal overlays, control shafts, etc.), particularly any exposed
metal part having a return path to the chassis should have a min-
imum resistor reading of 2.4M
and a maximum resistor reading
of 5.2M . Any resistance value below or above this range indi-
cates an abnormality which requires corrective action. An exposed
metal part having a return path to the chassis will indicate an open
circuit.
AC LEAKAGE TEST
ANY MEASUREMENTS NOT WITHIN THE LIMITS OUTLINED
ABOVE ARE INDICATIVE OF A POTENTIAL SHOCK HAZARD
AND MUST BE CORRECTED BEFORE RETURNING THE
RECEIVER TO THE CUSTOMER.
SAFETY PRECAUTIONS
Leakage Current Hot Check
Plug the AC line cord directly into a 120V AC 60Hz outlet (do not use
an isolated transformer for this check). Turn the AC power ON. Using
a Leakage Current Tester (Simpson's Model 228 or equivalent),
measure for current from all exposed metal parts of the cabinet
(antennas, screwheads, overlays, control shafts, etc.) particularly
any exposed metal part having a return path to the chassis or to a
known earth ground (water pipe, conduit, etc.). Any current meas-
ured must not exceed 0.5 MIU.
TABLE OF CONTENTS
(READING
SHOULD NOT
BE ABOVE
0.5 MIU)
3
LC37/LC37F
Many electrical and mechanical parts in HITACHI television
receivers have special safety-related characteristics. These are
often not evident from visual inspection nor can the protection
afforded by them necessarily be obtained by using replacement
components rated for higher voltage, wattage, etc. Replacement
parts which have these special safety characteristics are identified
in this Service Manual.
Electrical components having such features are identified with an
!
mark in the schematics and parts list in this Service Manual.
The use of a substitute replacement component which does not
have the same safety characteristics as the HITACHI-recom-
mended replacement component, shown in the parts list in this
Service Manual, may create shock, fire, or other hazards.
Production safety is continuously under review and new instruc-
tions are issued from time to time. For the latest information,
always consult the current HITACHI Service Manual. A subscrip-
tion to, or additional copies of HITACHI Service Manuals may be
obtained at a nominal charge from HITACHI Sales Corporation.
Ultraviolet Radiation
OPTIC UNIT: The primary source of Ultraviolet Radiation in this
receiver is the optic unit. The optic unit utilized in this chassis is
specially constructed to limit Ultraviolet Radiation emissions. For
continued Ultraviolet Radiation protection, the replacement optic
unit must be the same type as the original HITACHI-approved
type.
Service Personnel - WARNING
Eye damage may result from directly viewing the light produced by
the lamp used in this product. Always turn off lamp before open-
ing optic unit. Ultraviolet radiation eye protection required during
servicing.
When troubleshooting and making test measurements in a receiv-
er with an excessive high voltage problem, avoid being unneces-
sarily close to the optic unit and the high voltage component.
Do not operate the chassis longer than is necessary to locate the
cause of excessive voltage.
This Service Manual is intended for qualified service techni-
cians; it is not meant for the casual do-it-yourselfer. Qualified
technicians have the necessary test equipment and tools, and
have been trained to properly and safely repair complex prod-
ucts such as those covered by this manual. Improperly per-
formed repairs can adversely affect the safety and reliability of
the product and may void warranty. Consumers should not risk
trying to do the necessary repairs and should refer to a quali-
fied service technician.
WARNING
Lead in solder used in this product is listed by the California Health
and Welfare agency as a known reproductive toxicant which may
cause birth defects or other reproductive harm (California Health
and Safety Code, Section 25249.5).
When servicing or handling circuit boards and other compo-
nents which contain lead in solder, avoid unprotected skin
contact with solder. Also, when soldering do not inhale any
smoke or fumes produced.
SAFETY NOTICE
USE ISOLATION TRANSFORMER
WHEN SERVICING
Components having special safety characteristics identi-
fied by !
on the parts list in this service manual and its
supplements and bulletins. Before servicing this product, it
is important that the service technician read and follow the
"Safety Precautions" and the "Product Safety Notices" in
this Service Manual.
For continued ultraviolet protection, replace optic unit with
original type or HITACHI equivalent type.
POWER SOURCE
This television receiver is designed to operate on 120
Volts/60Hz, AC house current. Insert the power cord into
a 120 Volts/60Hz outlet.
NEVER CONNECT THE TV TO OTHER THAN THE
SPECIFIED VOLTAGE OR TO DIRECT CURRENT.
CAUTION!
The following symbol near the fuse indicates fast operat-
ing fuse (to be replaced). Fuse ratings appear within the
symbol.
Example:
The rating of fuse F901 is 6.0A-125V.
Replace with the same type of fuse for continued protec-
tion against fire.
The lamp in this product contains Mercury.
Dispose of properly in accordance with applicable
environmental laws. For Recycling and Disposal
information, contact your respective governmen-
tal agencies or the Electronic Industries Alliance
at www.eiae.org (in the U.S.) or Electronic
Product Stewardship Canada at www.epsc.ca (in
Canada).
PRODUCT SAFETY NOTICE
125V
6A
F901
NOTE:
TABLE OF CONTENTS
4
LC37/LC37F
CAUTION:
Before servicing instruments covered by this service
data and its supplements and addenda, read and follow the SAFE-
TY PRECAUTIONS on page 2 of this publication.
NOTE: If unforseen circumstances create conflict between the fol-
lowing SERVICING PRECAUTIONS and any of the SAFETY PRE-
CAUTIONS on page 2 of this publication, always follow the SAFETY
PRECAUTIONS.
Remember: Safety First.
General Servicing Guidelines
1.
Always unplug the instrument AC power cord from the AC power
source before:
a.
Removing or reinstalling any component, circuit board,
module, or any other instrument assembly.
b.
Disconnecting or reconnecting any instrument electrical
plug or other electrical connection.
c.
Connecting a test substitute in parallel with an electrolyt-
ic capacitor in the instrument.
CAUTION: A wrong part substitution or incorrect
polarity installation of electrolytic
capacitors may result in an
explosion hazard.
2.
Do not spray chemicals on or near this instrument or any of its
assemblies.
3.
Unless specified otherwise in these service data, clean electri-
cal contacts by applying the following mixture to the contacts
with a pipe cleaner, cotton-tipped stick or comparable nonabra-
sive applicator: 10% (by volume) Acetone and 90% (by volume)
ispropyle alchohol (90%-99% strength).
CAUTION: This is a flammable mixture. Unless specified
otherwise in these service data, lubrication of
contacts is not required.
4.
Do not defeat any plug/socket B+ voltage interlocks with which
instruments covered by this service data might be equipped.
5.
Do not apply AC power to this instrument and/or any of its elec-
trical assemblies unless all solid-state device heat-sinks are cor-
rectly installed.
6.
Always connect the test instrument ground lead to the appropri-
ate instrument chassis ground before connecting the test instru-
ment positive lead. Always remove the test instrument ground
lead last.
7.
Use with this instrument only the test fixtures specified in this
service data.
CAUTION: Do not connect the test fixture ground strap to
any heatsink in this instrument.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid state) devices can be damaged easily
by static electricity.
Such components commonly are called
Electrostatically Sensitive (ES) Devices.
Examples of typical ES
devices are integrated circuits and some field-effect transistors and
semiconductor "chip" components. The following techniques should
be used to help reduce the incidence of component damage caused
by static electricity.
1.
Immediately before handling any semiconductor component or
semiconductor-equipped assembly, drain off any electrostatic
charge on your body by touching a known earth ground.
Alternatively, obtain and wear a commercially available dis-
charging wrist strap device, which should be removed for poten-
tial shock reasons prior to applying power to the unit under test.
2.
After removing an electrical assembly equipped with ES
devices, place the assembly on a conductive surface such as
aluminum foil, to prevent electrostatic charge build-up or expo-
sure of the assembly.
3.
Use only a grounded-tip soldering iron to solder or desolder ES
devices.
4.
Use only an anti-static type solder removal device. Some sol-
der removal devices not classified as "anti-static" can generate
electrical charges sufficient to damage ES device.
5.
Do not use freon-propelled chemicals.
These can generate
electrical charges sufficient to damage ES devices.
6.
Do not remove a replacement ES device from its protective
package until immediately before you are ready to install it.
(Most replacement ES devices are packaged with leads electri-
cally shorted together by conductive foam, aluminum foil or
comparable conductive material.)
7.
Immediately before removing the protective material from the
leads of a replacement ES device, touch the protective material
to the chassis or circuit assembly into which the device will be
installed.
CAUTION: Be sure no power is applied to the chassis or
circuit, and observe all other safety precautions.
8.
Minimize bodily motions when handling unpackaged replace-
ment ES devices.
(Otherwise harmless motion such as the
brushing together of your clothes fabric or the lifting of your foot
from a carpeted floor can generate static electricity sufficient to
damage an ES device.)
SERVICING PRECAUTIONS
TABLE OF CONTENTS
5
LC37/LC37F
General Soldering Guidelines
1.
Use a grounded-tip, low-wattage soldering iron and appropriate
tip size and shape that will maintain tip temperature within the
range 500°F to 600°F.
2.
Use an appropriate gauge of resin-core solder composed of 60
parts tin/40 parts lead.
3.
Keep the soldering iron tip clean and well-tinned.
4.
Thoroughly clean the surfaces to be soldered. Use a small wire-
bristle (0.5 inch or 1.25 cm) brush with a metal handle. Do not
use freon-propelled spray-on cleaners.
5.
Use the following desoldering technique.
a.
Allow the soldering iron tip to reach normal temperature
(500°F to 600°F).
b.
Heat the component lead until the solder melts. Quickly
draw away the melted solder with an anti-static, suction-
type solder removal device or with solder braid.
CAUTION: Work quickly to avoid overheating the circuit
board printed foil.
6.
Use the following soldering technique.
a.
Allow the sodering iron tip to reach normal temperature
(500°F to 600°F).
b.
First, hold the soldering iron tip and solder strand against
the component lead until the solder melts.
c.
Quickly move the soldering iron tip to the junction of the
component lead and the printed circuit foil, and hold it
there only until the solder flows onto and around both the
component lead and the foil.
CAUTION: Work quickly to avoid overheating the circuit
board printed foil or components.
d.
Closely inspect the solder area and remove any excess
or splashed solder with a small wire-bristle brush.
IC Removal/Replacement
Some Hitachi unitized chassis circuit boards have slotted holes
(oblong) through which the IC leads are inserted and then bent flat
against the circuit foil. When holes are the slotted type, the follow-
ing technique should be used to remove and replace the IC. When
working with boards using the familiar round hole, use the standard
technique as outlined in paragraphs 5 and 6 above.
Removal
1.
Desolder and straighten each IC lead in one operation by gent-
ly prying up on the lead with the soldering iron tip as the solder
melts.
2.
Draw away the melted solder with an anti-static suction-type sol
der removal device (or with solder braid) before removing the
IC.
Replacement
1.
Carefully insert the replacement IC in the circuit board.
2.
Carefully bend each IC lead against the circuit foil pad and
solder it.
3.
Clean the soldered areas with a small wire-bristle brush. (It is
not necessary to reapply acrylic coating to areas.)
"Small-signal" Discrete Transistor Removal/Replacement
1.
Remove the defective transistor by clipping its leads as close as
possible to the component body.
2.
Bend into a "U" shape the end of each of three leads remain-
ing on the circuit board.
3.
Bend into a "U" shape the replacement transistor leads.
4.
Connect to replacement transistor leads to the corresponding
leads extending from the circuit board and crimp the "U" with
long nose pliers to insure metal to metal contact, then solder
each connection.
Power Output Transistor Devices Removal/Replacement
1.
Heat and remove all solder from around the transistor leads.
2.
Remove the heatsink mounting screw (if so equipped).
3.
Carefully remove the transistor from the circuit board.
4.
Insert new transistor in circuit board.
5.
Solder each transistor lead, and clip off excess lead.
6.
Replace heatsink.
Diode Removal/Replacement
1.
Remove defective diode by clipping its leads as close as pos-
silbe to diode body.
2.
Bend the two remaining leads perpendicularly to the circuit
board.
3.
Observing diode polarity, wrap each lead of the new diode
around the corresponding lead on the circuit board.
4.
Securely crimp each connection and solder it.
5.
Inspect (on the circuit board copper side) the solder joints of
the two "original leads". If they are not shiny, reheat them
and, if necessary, apply additional solder.
Use Soldering Iron to Pry Leads